Widely used are fitted or contoured bed sheets with side and end panels which conform to the edges of the mattress to which the bed sheet is fitted.
The commonly available bed sheets of this type rely on elastic straps to hold the bed sheet in place. This system is comparatively ineffective, and the bed sheet can be easily dislodged by the movements of one sleeping or lying on the mattress. The bed can then become uncomfortable, requiring that the bed sheet be put back in place. Particularly in the middle of the night, this can be a major inconvenience.
A number of systems for more securely holding a fitted bed sheet in place on a mattress have been proposed and disclosed in the following U.S. patents:
______________________________________ Patent Number Title Issue Date ______________________________________ 2,727,253 Contour sheets for 12/20/55 mattresses 2,857,643 Contour sheets 5/28/56 3,256,038 Tensioning device 9/15/64 for fabric covers 3,858,256 Fitted bedclothes 1/7/75 4,495,233 Removable cover 1/22/85 adapted to cover three-dimensional articles 4,660,240 Device for 4/28/87 attaching sheets to a waterbed 4,727,608 Fitted bed sheet 3/1/88 and method of making same 4,891,856 Grasping system 12/27/88 for use with a contoured sheet 4,937,904 Fitted sheet with 7/3/90 sheet retainer 5,046,207 Adjustable bed 9/10/91 sheet ______________________________________
It is not believed that any of these patented bed sheet retainer systems have ever become commercially available. This is understandable as those systems seem to suffer such disadvantages as ineffectiveness, complexity, and the inability to be used with conventional fitted sheets.
Above-cited U.S. Pat. Nos. 2,857,643 and 4,660,240 disclose fitted bed sheet retainer systems with two-piece connectors or fasteners for securing tensioning straps to the corners of a fitted sheet. The fasteners disclosed in the '240 patent have a major drawback; they can be used only in applications in which there is a structural member to which the fastener can be attached by wood screws. Consequently, these fasteners are of limited application and certainly cannot be used to secure a fitted bed sheet to a conventional mattress.
Thus, there is a need for better ways of securing a fitted bed sheet in place on a mattress.
The '643 patent discloses a bed sheet retaining system which employs hose-type fasteners. These fasteners are difficult to use, or even impractical, if the fabric to which they are attached is thick, folded, or otherwise bulky. Furthermore, anchoring a pair of these fasteners in the requisite linear relationship needed to connect a retainer strap between the fasteners can prove awkward, at best.
Therefore, there is also a continuing need for fasteners which are versatile in that they can be secured to fabrics of widely varying thickness and in that they do not require wood screws or other devices to secure the fastener in place.